Some of the text in this entry was rewritten from Los Alamos National Laboratory - Californium. Additional text was taken directly from the Elements database 20001107 (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table were obtained from the sources listed on the subject page and Wikipedia:WikiProject Elements but were reformatted and converted into SI units.
The content that was previously listed in the history section was deleted due to reasons of (1) immateriality and (2) cause for undue alarm to present users of californium. If in the unlikely event the DOE halts californium production, only then should the deleted material be reinserted. —Preceding unsigned comment added by Integrity84 ( talk • contribs) 23:39, 10 November 2008 (UTC)
It is quite regrettable that someone who wishes to cause undue alarm to users of californium-252 has hijacked this Wikipedia page and is spreading malicious untruths. The statement, “This will leave the Russian facility at Dmitrovgrad as the sole source of the radioisotope,” is simply untrue. It should in the very least be modified to say, “If this decision were upheld,…”. The unscrupulous hijacker goes on to write “…this is a primary driver behind the sudden cut-off”. Well, any informed person would know that there has been no cut-off from the DOE. The DOE continues to irradiate curium targets at its HFIR reactor to make into Cf 252, and they recently removed a batch for processing into Cf 252, to handle industry needs out through 2012. The likelihood that the US DOE will cease manufacturing Cf 252 is extremely low. In fact, if this hijacker had any integrity at all, they would say that the DOE admitted they had made a mistake in announcing that they were no longer going to manufacture Cf 252.
It’s unfortunate that the open environment of Wikipedia is vulnerable to such biased editing and to the underhanded tactics, in this case, of a vendor who is promoting neutron generators. The statement that “neutron generators have recently become cost effective” is another untruth. On an apples vs. apples basis, they are still 3-4 times more expensive than Cf 252, which is not close to being cost competitive. This sentence is nothing more than crass commercialism by a vendor of neutron generators, such as Sodern. I guess they’ve been infected by the negative advertising that dominated the recent US presidential race.
More importantly, if one views this discussion of recent events in the availability of Cf 252 (a small bump in a long road) against the rest of the content on this site, it doesn’t meet the test of materiality. Integrity84 ( talk) 22:37, 7 November 2008 (UTC)
no resonoble sorces take it off the page henry ( talk) 05:00, 22 November 2008 (UTC)
I've just been related a story from an ex-Soviet nuclear engineer. He said Californium was a problematic element to work with because it exhibits explosive decay; the element decays, splitting off a Helium atom (quite heavy), which given the rate of decay will quickly coat a room in radioactive dust. The attraction of it was it acted as a good calibration element, with a 2.5 year half-life, and it releases many neutrons when an atom splits. How do we add information like that to the article? Josh Parris ✉ 00:24, 22 Jun 2005 (UTC)
The French phrase en masse has the connotation of "all together", that is, a group of people acting as one. It is not used to refer to "mass quantities" of a substance. Tex 20:06, 22 February 2006 (UTC)
This Straight Dope link states that californium-252 is "the most expensive substance in the world". While this sort of rubbishy overstatement pisses me off excessively, does anyone think this should be in the article? If it's correct, that is... although Cecil and his minions usually are. — — riana_dzasta • t • c • e • ER • 22:41, 6 July 2006 (UTC)
in a national geographic article (july '02) it said one miligram of californium 252 cost $68,000 (or $68,000,000 for a gram) Soyseñorsnibbles ( talk) 03:28, 26 November 2007 (UTC)
Industrial users pay approximately $100 US per microgram for Cf 252, as of summer 2008. This cost is expected to skyrocket at least three-fold if U.S. Department of Energy actually halts production. —Preceding unsigned comment added by 151.200.14.162 ( talk) 20:26, 2 July 2008 (UTC)
can we agree that there are many sorces conflicting but yet we have no real source on the page time to take it off henry ( talk) 05:02, 22 November 2008 (UTC)
The claim should stay off the article, because it's hard to define and by many definitions not true. Antiprotons are vastly more expensive, though they aren't "sold", so to speak. A back of the envelope estimate gives their cost to be something like a quintillion dollars/gram (might be better at CERN now). Silpion ( talk) 22:02, 25 October 2009 (UTC)
I know that you cant obtain Californium naturally, but since you can artificially manufacture it, why is the appearance stated as "unknown" ? Forgive my ignorance but surely you can sneak a peek at it while it (temporarily) exists, cant you ?
The below text needs to be cited before being placed back in the article. -- mav ( reviews needed) 02:35, 20 September 2010 (UTC)
Their neutron capture cross-sections are :
Capture | Fission | HL | |||
---|---|---|---|---|---|
Th | RI | Th | RI | ( a) | |
250Cf | 2000 | 12000 | 13.1 | ||
251Cf | 2900 | 1600 | 4800 | 5500 | 898 |
252Cf | 20 | 44 | 32 | 1100 | 2.645 |
Thus californium-250 and californium-251 will be transmuted fairly quickly, with the majority undergoing nuclear fission at the mass 251, but with a large fraction surviving to become californium-252. The californium-252 will not be transmuted or destroyed quickly in a well-thermalized reactor, but it has a short decay half-life. These isotopes decay into long-lived isotopes of curium.
Californium-252 has a relatively high rate of spontaneous fission. Although still much less likely than alpha decay, this makes californium a significant neutron radiation emitter. Manufactured MOX fuel that contains enough curium would likely also contain enough californium after its use to preclude manual handling of the spent fuel, or its nuclear reprocessing products, with mere glove boxes -- that protects against alpha and beta radiation, but not against energetic gamma radiation and especially not against neutron radiation.
On November 1, 1952, the nuclear fallout of the world's first large hydrogen bomb test, the Ivy Mike test explosion at Eniwetok Atoll, in the Central Pacific Ocean contained detectable trace amounts of americium, curium, californium, berkelium, einsteinium, and fermium. These elements had been created by the repeated bombardment of nuclei of uranium and plutonium, and their products, by multiple neutrons during this nuclear weapons test, followed by multiple beta decays. Thus, amounts of element 92 were bootstrapped all the way up detectable amounts of elements 99 and 100. In the physics laboratories, the atomic numbers of these elements could be dermined by the characteristic X-rays that they produced when bombarded with energetic electrons - using the methods invented by Henry Gwyn Jeffreys Moseley in England over 30 years earlier.
is File:Actinidesvsfissionproducts uncomp.png better than the template in use now? Nergaal ( talk) 23:26, 26 September 2010 (UTC)
Who are the person to confuse California with Californium? Neither an English speaker nor a foreign person proficient enough to read English. There is (AFAIK) no way to confuse the letter "a" with "u" followed by "m". They don't look alike. Rursus dixit. ( mbork3!) 18:53, 14 November 2010 (UTC)
Using ADSABS here searching for californium and supernova I get some abstracts from 1956 and 1957 and one from 1959 explaining that the alleged Cf-254 decay is instead Fe-59 decay. Thereafter nothing! I believe that this alleged natural occurrence of Cf is a tall story originating from an obsolete theory on main energy production in supernovae. Given the low occurrence of Cf in atomic bombs, and the high occurrence of radioactive isotopes near the iron peak in supernova spectra, it is reasonable to assume that there is no Cf detected in supernovae (although the element may actually exist in trace amounts for a short while in layers that was near the core). Rursus dixit. ( mbork3!) 12:36, 30 November 2010 (UTC)
I just added this text in a ref note at the end of the occurrence section. Please feel free to modify. -- mav ( reviews needed) 14:21, 5 March 2011 (UTC)
The article now has the sourced statement "Each microgram of fresh californium[-252] produces 170 million neutrons per minute." However, a source from ORNL gives the rather lower figure of 2.314 million neutrons per second. They can't both be right. Anyone? Oliphaunt ( talk) 21:53, 22 December 2010 (UTC)
is said to be orange-red in de.wiki article, and it is correct according to this source. I failed to get snippets from two other sources in the article (or any other sources), which were supposedly saying it is lemon-yellow or pale-green or both, and thus just removed green to avoid article contradicting itself. Comments? Materialscientist ( talk) 10:56, 14 February 2011 (UTC)
In the introduction, it is Cf-249, not Cf-252, that has a half life of 351 years. Under Production, "curium isotopes 244 to 248 are irradiated by neutrons in special reactors to produce primarily californium-242" should obviously be californium-252. 69.72.27.179 ( talk) 08:16, 21 February 2011 (UTC)
Suggested link: Neutron cross-section. For the sentence "collecting neutrons (high neutron capture) and tendency to interact with other particles (high cross section)". Not added myself, as I might miss a subtle point here, and the neutron capture link is still useful. In particular, Neutron capture#Capture cross section does what the Neutron cross-section article (which explains why scattering cross-section varies) fails to do - namely explain why certain nuclei are more likely to absorb neutrons than others. From what I can tell, it depends on the neutron energy and the resonance integral. Also, possibly more useful than cross section (physics) (currently linked) is the article nuclear cross section and/or the article absorption cross section (as opposed to scattering cross-sections).
What I am really looking for is an explanation as to why californium-251 has a lower yield than the other isotopes produced by neutron radiation of berkelium, and when I follow the links, it doesn't really help. It there a source that would be useful for further reading on this topic? Carcharoth ( talk) 06:48, 12 March 2011 (UTC)
It's on GA for the moment, since we've agreed that GA is higher than A on WP:ELEM. Lanthanum-138 ( talk) 13:27, 9 April 2011 (UTC)
Please list issues here.
Hopefully some of those comments will be of use. I'll check back over the next few days and see if anything else comes up on a second reading. Carcharoth ( talk) 05:47, 6 March 2011 (UTC)
Above text copied from archived FAC page with addressed and struck items removed. If I deleted any comments that were not completely addressed, then please re-add them. Please also add any other comments on things that need to be improved before re-submittal to FAC. -- mav ( reviews needed) 11:15, 12 March 2011 (UTC)
GA toolbox |
---|
Reviewing |
Reviewer: FRE YWA 05:49, 25 April 2011 (UTC)
After the success of beryllium (see here), I am now going to review californium. This should go without a hitch or else you're fired! FRE YWA 05:49, 25 April 2011 (UTC) GA review – see WP:WIAGA for criteria
The article is decent, but one last thing to do before I do the GA ritual.
I'm now going through the article and fixing up all the punctuation errors...anybody who finds those I missed, feel free to correct them too. Lanthanum-138 ( talk) 10:29, 25 April 2011 (UTC)
{{
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: Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite book}}
: Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)
Some of the text in this entry was rewritten from Los Alamos National Laboratory - Californium. Additional text was taken directly from the Elements database 20001107 (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table were obtained from the sources listed on the subject page and Wikipedia:WikiProject Elements but were reformatted and converted into SI units.
The content that was previously listed in the history section was deleted due to reasons of (1) immateriality and (2) cause for undue alarm to present users of californium. If in the unlikely event the DOE halts californium production, only then should the deleted material be reinserted. —Preceding unsigned comment added by Integrity84 ( talk • contribs) 23:39, 10 November 2008 (UTC)
It is quite regrettable that someone who wishes to cause undue alarm to users of californium-252 has hijacked this Wikipedia page and is spreading malicious untruths. The statement, “This will leave the Russian facility at Dmitrovgrad as the sole source of the radioisotope,” is simply untrue. It should in the very least be modified to say, “If this decision were upheld,…”. The unscrupulous hijacker goes on to write “…this is a primary driver behind the sudden cut-off”. Well, any informed person would know that there has been no cut-off from the DOE. The DOE continues to irradiate curium targets at its HFIR reactor to make into Cf 252, and they recently removed a batch for processing into Cf 252, to handle industry needs out through 2012. The likelihood that the US DOE will cease manufacturing Cf 252 is extremely low. In fact, if this hijacker had any integrity at all, they would say that the DOE admitted they had made a mistake in announcing that they were no longer going to manufacture Cf 252.
It’s unfortunate that the open environment of Wikipedia is vulnerable to such biased editing and to the underhanded tactics, in this case, of a vendor who is promoting neutron generators. The statement that “neutron generators have recently become cost effective” is another untruth. On an apples vs. apples basis, they are still 3-4 times more expensive than Cf 252, which is not close to being cost competitive. This sentence is nothing more than crass commercialism by a vendor of neutron generators, such as Sodern. I guess they’ve been infected by the negative advertising that dominated the recent US presidential race.
More importantly, if one views this discussion of recent events in the availability of Cf 252 (a small bump in a long road) against the rest of the content on this site, it doesn’t meet the test of materiality. Integrity84 ( talk) 22:37, 7 November 2008 (UTC)
no resonoble sorces take it off the page henry ( talk) 05:00, 22 November 2008 (UTC)
I've just been related a story from an ex-Soviet nuclear engineer. He said Californium was a problematic element to work with because it exhibits explosive decay; the element decays, splitting off a Helium atom (quite heavy), which given the rate of decay will quickly coat a room in radioactive dust. The attraction of it was it acted as a good calibration element, with a 2.5 year half-life, and it releases many neutrons when an atom splits. How do we add information like that to the article? Josh Parris ✉ 00:24, 22 Jun 2005 (UTC)
The French phrase en masse has the connotation of "all together", that is, a group of people acting as one. It is not used to refer to "mass quantities" of a substance. Tex 20:06, 22 February 2006 (UTC)
This Straight Dope link states that californium-252 is "the most expensive substance in the world". While this sort of rubbishy overstatement pisses me off excessively, does anyone think this should be in the article? If it's correct, that is... although Cecil and his minions usually are. — — riana_dzasta • t • c • e • ER • 22:41, 6 July 2006 (UTC)
in a national geographic article (july '02) it said one miligram of californium 252 cost $68,000 (or $68,000,000 for a gram) Soyseñorsnibbles ( talk) 03:28, 26 November 2007 (UTC)
Industrial users pay approximately $100 US per microgram for Cf 252, as of summer 2008. This cost is expected to skyrocket at least three-fold if U.S. Department of Energy actually halts production. —Preceding unsigned comment added by 151.200.14.162 ( talk) 20:26, 2 July 2008 (UTC)
can we agree that there are many sorces conflicting but yet we have no real source on the page time to take it off henry ( talk) 05:02, 22 November 2008 (UTC)
The claim should stay off the article, because it's hard to define and by many definitions not true. Antiprotons are vastly more expensive, though they aren't "sold", so to speak. A back of the envelope estimate gives their cost to be something like a quintillion dollars/gram (might be better at CERN now). Silpion ( talk) 22:02, 25 October 2009 (UTC)
I know that you cant obtain Californium naturally, but since you can artificially manufacture it, why is the appearance stated as "unknown" ? Forgive my ignorance but surely you can sneak a peek at it while it (temporarily) exists, cant you ?
The below text needs to be cited before being placed back in the article. -- mav ( reviews needed) 02:35, 20 September 2010 (UTC)
Their neutron capture cross-sections are :
Capture | Fission | HL | |||
---|---|---|---|---|---|
Th | RI | Th | RI | ( a) | |
250Cf | 2000 | 12000 | 13.1 | ||
251Cf | 2900 | 1600 | 4800 | 5500 | 898 |
252Cf | 20 | 44 | 32 | 1100 | 2.645 |
Thus californium-250 and californium-251 will be transmuted fairly quickly, with the majority undergoing nuclear fission at the mass 251, but with a large fraction surviving to become californium-252. The californium-252 will not be transmuted or destroyed quickly in a well-thermalized reactor, but it has a short decay half-life. These isotopes decay into long-lived isotopes of curium.
Californium-252 has a relatively high rate of spontaneous fission. Although still much less likely than alpha decay, this makes californium a significant neutron radiation emitter. Manufactured MOX fuel that contains enough curium would likely also contain enough californium after its use to preclude manual handling of the spent fuel, or its nuclear reprocessing products, with mere glove boxes -- that protects against alpha and beta radiation, but not against energetic gamma radiation and especially not against neutron radiation.
On November 1, 1952, the nuclear fallout of the world's first large hydrogen bomb test, the Ivy Mike test explosion at Eniwetok Atoll, in the Central Pacific Ocean contained detectable trace amounts of americium, curium, californium, berkelium, einsteinium, and fermium. These elements had been created by the repeated bombardment of nuclei of uranium and plutonium, and their products, by multiple neutrons during this nuclear weapons test, followed by multiple beta decays. Thus, amounts of element 92 were bootstrapped all the way up detectable amounts of elements 99 and 100. In the physics laboratories, the atomic numbers of these elements could be dermined by the characteristic X-rays that they produced when bombarded with energetic electrons - using the methods invented by Henry Gwyn Jeffreys Moseley in England over 30 years earlier.
is File:Actinidesvsfissionproducts uncomp.png better than the template in use now? Nergaal ( talk) 23:26, 26 September 2010 (UTC)
Who are the person to confuse California with Californium? Neither an English speaker nor a foreign person proficient enough to read English. There is (AFAIK) no way to confuse the letter "a" with "u" followed by "m". They don't look alike. Rursus dixit. ( mbork3!) 18:53, 14 November 2010 (UTC)
Using ADSABS here searching for californium and supernova I get some abstracts from 1956 and 1957 and one from 1959 explaining that the alleged Cf-254 decay is instead Fe-59 decay. Thereafter nothing! I believe that this alleged natural occurrence of Cf is a tall story originating from an obsolete theory on main energy production in supernovae. Given the low occurrence of Cf in atomic bombs, and the high occurrence of radioactive isotopes near the iron peak in supernova spectra, it is reasonable to assume that there is no Cf detected in supernovae (although the element may actually exist in trace amounts for a short while in layers that was near the core). Rursus dixit. ( mbork3!) 12:36, 30 November 2010 (UTC)
I just added this text in a ref note at the end of the occurrence section. Please feel free to modify. -- mav ( reviews needed) 14:21, 5 March 2011 (UTC)
The article now has the sourced statement "Each microgram of fresh californium[-252] produces 170 million neutrons per minute." However, a source from ORNL gives the rather lower figure of 2.314 million neutrons per second. They can't both be right. Anyone? Oliphaunt ( talk) 21:53, 22 December 2010 (UTC)
is said to be orange-red in de.wiki article, and it is correct according to this source. I failed to get snippets from two other sources in the article (or any other sources), which were supposedly saying it is lemon-yellow or pale-green or both, and thus just removed green to avoid article contradicting itself. Comments? Materialscientist ( talk) 10:56, 14 February 2011 (UTC)
In the introduction, it is Cf-249, not Cf-252, that has a half life of 351 years. Under Production, "curium isotopes 244 to 248 are irradiated by neutrons in special reactors to produce primarily californium-242" should obviously be californium-252. 69.72.27.179 ( talk) 08:16, 21 February 2011 (UTC)
Suggested link: Neutron cross-section. For the sentence "collecting neutrons (high neutron capture) and tendency to interact with other particles (high cross section)". Not added myself, as I might miss a subtle point here, and the neutron capture link is still useful. In particular, Neutron capture#Capture cross section does what the Neutron cross-section article (which explains why scattering cross-section varies) fails to do - namely explain why certain nuclei are more likely to absorb neutrons than others. From what I can tell, it depends on the neutron energy and the resonance integral. Also, possibly more useful than cross section (physics) (currently linked) is the article nuclear cross section and/or the article absorption cross section (as opposed to scattering cross-sections).
What I am really looking for is an explanation as to why californium-251 has a lower yield than the other isotopes produced by neutron radiation of berkelium, and when I follow the links, it doesn't really help. It there a source that would be useful for further reading on this topic? Carcharoth ( talk) 06:48, 12 March 2011 (UTC)
It's on GA for the moment, since we've agreed that GA is higher than A on WP:ELEM. Lanthanum-138 ( talk) 13:27, 9 April 2011 (UTC)
Please list issues here.
Hopefully some of those comments will be of use. I'll check back over the next few days and see if anything else comes up on a second reading. Carcharoth ( talk) 05:47, 6 March 2011 (UTC)
Above text copied from archived FAC page with addressed and struck items removed. If I deleted any comments that were not completely addressed, then please re-add them. Please also add any other comments on things that need to be improved before re-submittal to FAC. -- mav ( reviews needed) 11:15, 12 March 2011 (UTC)
GA toolbox |
---|
Reviewing |
Reviewer: FRE YWA 05:49, 25 April 2011 (UTC)
After the success of beryllium (see here), I am now going to review californium. This should go without a hitch or else you're fired! FRE YWA 05:49, 25 April 2011 (UTC) GA review – see WP:WIAGA for criteria
The article is decent, but one last thing to do before I do the GA ritual.
I'm now going through the article and fixing up all the punctuation errors...anybody who finds those I missed, feel free to correct them too. Lanthanum-138 ( talk) 10:29, 25 April 2011 (UTC)
{{
cite journal}}
: Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite book}}
: Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)